GEEK ALERT: When Mean Isn't Median AND Median Isn't Mode

GEEK SPEAK WARNING!  However, discussed in a way all can understand.


Quick definitions -- Median = Half Above/Half Below; Mode = Most Commonly Observed Data Point;  Mean = Average.  Take your standard bell curve.

On this curve,the vertical line in the center represents the mean, median, and mode.  But in the "real" world the results we observe don't always fit this curve.  Let's focus this discussion on the question of Median and Mode.  I'll save the Mean, no pun intended, discussion for a later time.


In the 2008 Presidential Election, our model generated the following chart:

Forecast: Tsunami Warning Issued for House; Storm Clouds Gather in Senate

Post for October 29, 2010 --


New polling in both the House and Senate served to both clarify and obscure expected results for this coming Tuesday.
  
Polling in Maine by Critical Insights shows potentially close races in both of the state's two Congressional districts: 

• ME-1:   Republican Dean Scontras  leading (but well within the margin of error) Rep. Chellie Pingree by a margin of 45-41.  Two weeks ago the same pollster showed Pingree leading by 45-40.  The significant note is that Critical Insights' poll from the middle of May showed Pingree with a 24 point lead.
• ME-2:   Republican Jason Levesque trails incumbent Democratic Rep. Mike Michaud by a margin of 44-40 (also within the margin of error).  Two weeks ago Critical Insights' polled the district and found Michaud leading by 19.

Significance: If Democrats were to lose both of these seats in a state where polls close relatively early, Republican gains will be massive.


As it is, our model's evaluation of InTrade data suggests only "huge" gains of approximately 60 seats from their post 2008 election level.  Friday's analysis gives Republicans 237 seats in the next Congress.  The Republican probability of taking the House 92.3% under our model.  On our 2006 vintage InTrade analysis on the Friday preceding the election, Democrats' chance of taking the House was 72%.  Democrats gains 31 seats (compared to post 2004 elections) that year.    The probability of that size of gain (30 or more seats) on Friday before the election was 35.4%.  That is roughly the same probability our model generates for gains of 65+ using InTrade data based on Friday data.   Non-scientific observation: Friday before election data appears to have UNDERESTIMATED election day results in the House. 


Friday's Daily Snapshot and House Pictures

Our Senate analysis makes Democrats the favorites to maintain control of the Senate.  Our analysis of InTrade data suggests that Republicans will hold at least 49 seats.  Politically, this means Democrats control; for InTrading purposes it means Neither Party to Control contract would prevail.  In fact, our modelling suggests that on a tighter trend analysis, Republicans may well end up with 50 seats or better.

Here are the Senate pictures.

Increasingly, the data seems to suggest that Pennsylvania's appearance on the screen ten days ago was a "false warning."  Data increasingly suggests Pennsylvania may be well beyond Democratic efforts to save the seat.   There are increasing signs that recent polling data showing Washington within a point either way are no longer the exceptions, but the consensus among pollsters.


Questions of the day.   Add your input and observations.




1.   Will Senator Lisa Murkowski's write-in bid cost Republicans control of the Senate?

InTrade data currently favors Lisa Murkowski to win, but the situation is volatile.  Democrats are still an underdog in the seat, BUT the DSCC is spending money there.  The Republican Senate nightmare ... win two of WV, WA, and CA ... and then find out you don't control the Senate because of Alaska.  Think it's possible? Probable? Or No Way that Happens? 

2.   What Senate race will be the biggest surprise on Tuesday?

Republican House 90%; 49 Republican Senators

90% Probability of a Republican House


Pundits are almost universal in predicting a Republican House takeover next Tuesday.  Our model based on InTrade market data agrees pegging Republicans as a 90% favorite to do so.  The House debate right now centers around the question of how high the Republican wave in House elections will be.  Some pundits argue that Republicans will only capture the House by a narrow majority.  Others argue that the GOP will end with their highest seat count since the 1940s or earlier.  Right now our model projects Republicans holding 236 seats in the next Congress.  An important caveat -- our model suggests that the risk for greater losses by Democrats exceeds the risk of significantly smaller Republican gains.

Is Today's Republican Uptick in Races and Micro Model Beginning of a Rally?


Republicans saw an uptick in their prospects in our 7 key races, yet remain an underdog in their battle to claim the Senate.  Our macro and micro model projections are only separated by 1/10th of a seat in today's analysis of InTrade data.  The micro model projects 48.9 seats and the macro model 49.0 seats.  In short, our micro model is catching up with the macro model.  We would expect them to move in close tandem from this point forward.

As mentioned earlier, Republicans started to retrace lost ground in all seven of the most competitive -- or key -- Senate races.  Illinois, Washington, and West Virginia all saw Republican improvement of more than 3%.  However, in West Virginia and Washington as sizable gain is still required to push those seats into "Republican Favored" territory.  The table below summarizes our model's pricing of Republican probabilities in Thursday nights data run.

Here is our daily chart of this month's pricing movement for the seven races included in the above table.  As you can see, volatility remains and is likely to pick up in at least 4 of the 7 seats over the weekend.

Be sure to check out our InTrade Portfolio on our InTrade portfolio page.  Additional charts on House and Senate control probabilities are posted below.